Tretinoin

Tretinoin, also known as all-trans retinoic acid (ATRA), is medication used for the treatment of acne and acute promyelocytic leukemia.[1][2][3] For acne, it is applied to the skin as a cream or ointment.[3] For leukemia, it is taken by mouth for up to three months.[1]

Common side effects when used by mouth include shortness of breath, headache, numbness, depression, skin dryness, itchiness, hair loss, vomiting, muscle pains, and vision changes.[1] Other severe side effects include high white blood cell counts and blood clots.[1] When used as a cream, side effects include skin redness, peeling, and sun sensitivity.[3] Use during pregnancy is known to harm the baby.[1] It is in the retinoid family of medications.[2]

In topical form, this drug is pregnancy category C and should not be used by pregnant women.[8]

People using the topical form should not also use any cream or lotion that has a strong drying effect, contains alcohol, astringents, spices, lime, sulfur, resorcinol, or aspirin, as these may interact with tretinoin or exacerbate its side effects.[8]

Tretinoin is used to induce remission in people with acute promyelocytic leukemia who have a mutation (the t(15;17) translocation 160 and/or the presence of the PML/RARα gene) and who don't respond to anthracyclines or can't take that class of drug. It is not used for maintenance therapy.[10][11][12]

In oral form, this drug is pregnancy category D and should not be used by pregnant women as it may harm the fetus.[10]

For its use in cancer, its mechanism of action is unknown, but on a cellular level, laboratory test show that tretinoin forces APL cells to differentiate and stops them from proliferating; in people there is evidence that it forces the primary cancerous promyelocytes to differentiate into their final form, allowing normal cells to take over the bone marrow.[10] Recent study shows that ATRA inhibits and degrades active PIN1.[13]

For its use in acne, the mechanism is unknown, but again on a cellular level there is evidence that it decreases the ability of epithelial cells in hair follicles to stick together, leading to fewer blackheads; it also seems to make the epithelial cells divide faster, causing the blackheads to be pushed out.[citation needed]

Tretinoin was co-developed for its use in acne by James Fulton and Albert Kligman when they were at University of Pennsylvania in the late 1960s.[14][15] The University of Pennsylvania held the patent for Retin-A, which it licensed to pharmaceutical companies.[15]